The present invention relates to a gas-insulated switchgear device for high- and medium-voltage applications, having improved functions and characteristics; the expression xe2x80x9chigh- and medium-voltage applicationsxe2x80x9d is used to reference applications with operating voltages equal to or above 1000 Volt.
In particular, the device according to the invention, by virtue of its innovative structure, allows to optimize execution of the required electric maneuvers, according to a solution which is at once simple, effective and compact.
It is known from the art that electric switching operations, for both interruption and disconnection, in gas-insulated circuit breaker and disconnector units are provided by virtue of the translatory motion of one or more moving contacts which can couple/uncouple with respect to corresponding fixed contacts. A significant drawback of known types of devices is the fact that the various switching operations, for example for disconnection on the input line or on the output line, are performed by means of dedicated components which are structurally separate and mutually distinct; in this way, the number of components used to implement the various switching operations is large and entails an increase in the space occupation and total volume of the device, with a consequent cost increase.
Furthermore, the contacts are moved by using actuation devices which generally comprise actuators of the mechanical or hydraulic type which require complicated kinematic systems to transmit motion to the moving contact. In particular, the disconnection maneuver requires the coordinated movement of one or more moving contacts, so that the opening/closure of the disconnection contacts occurs in the intended sequence. This usually entails complicated coupling mechanisms and/or complicated actuation and control systems, especially when disconnection occurs on multiple-bar systems. In view of the mechanical complexity of the movement elements and of the large number of components used, maintenance interventions are necessary in order to maintain nominal behavior and ensure repeatability of performance.
This structural complexity has an even worse impact when the various circuit breaker and disconnector units are used to provide substations. An example in this regard is shown in FIG. 1, which schematically illustrates a minimal configuration of an electrical substation of the single distribution bar type. As shown in said figure, each phase of the main power line 101 is connected in input to a corresponding distribution bar 100; at least one disconnector 102 and a current transformer 103 are used along the junction conductor that connects a phase of the line 101 to the corresponding bar 100. In turn, the bars 100 are electrically connected to a power transformer 104, which appropriately varies the voltage so as to obtain an adequate level thereof in input to a set of medium-voltage devices, generally designated by the reference numeral 105; ahead of the power transformer 104 there are also surge arresters 106 which protect the transformer against possible damage. A second disconnector 102, a second current transformer 103 and a circuit breaker 109 are used along the connection between each bar 100 and the power transformer 104. In output from the substation, each bar 100 is connected to the corresponding phase of the line 101 according to an architecture which is similar to the input architecture, i.e., by using another disconnector 102 and an additional current transformer 103.
In the most common applications, the minimum configuration of the electrical substation is generally conveniently supplemented by using additional primary components; in particular, two voltage transformers, two disconnectors and two circuit breakers are used for each phase of the main power line 101, arranging them respectively at the input connection and in output between the line phase and the bar of the substation. The substation is furthermore equipped with a series of secondary components, constituted by protection and control systems, in order to ensure the correct electrical operation of the system and avoid dangerous damage.
Owing to the large number of components required, even for the provision of a minimal configuration, known types of substation are unsatisfactory in practical use mainly due to their high cost, to their space occupation requirements and to the need for frequent maintenance. Said substations furthermore do not have a structure of the modular type which makes them conveniently flexible in their applications and easy to implement according to the various application requirements.
The aim of the present invention is to provide a gas-insulated switchgear device for high- and medium-voltage applications which is capable of integrating the functions that in the current art are performed by multiple structurally mutually distinct components.
Within the scope of this aim, an object of the present invention is to provide a gas-insulated switchgear device for high- and medium-voltage applications which allows great flexibility and simplicity in the execution of the required electric switching operations.
Another object of the present invention is to provide a gas-insulated switchgear device for high- and medium-voltage applications which has a compact structure and small dimensions, so as to significantly reduce the space occupation requirements.
Another object of the present invention is to provide a gas-insulated switchgear device for high- and medium-voltage applications which has a reduced mechanical complexity.
Another object of the present invention is to provide a gas-insulated switchgear device for high- and medium-voltage applications which easily allows to realize different application configurations, particularly for the implementation of substations with a single and/or double conducting bar system.
Another object of the present invention is to provide a gas-insulated switchgear device for high- and medium-voltage applications which is highly reliable, relatively easy to manufacture and at competitive costs.
This aim, these objects and others which will become apparent hereinafter are achieved by a gas-insulated switchgear device for high- and medium-voltage applications, characterized in that it comprises an enclosure which contains a disconnection unit which is electrically connected to a first electric terminal and is arranged in the enclosure in a substantially central position, and a first interruption unit and a second interruption unit which are connected electrically to the disconnection unit and, respectively, to a second electric terminal and a third electric terminal, said first and second interruption units being arranged mutually opposite with respect to the disconnection unit.
The device according to the invention can be of the segregated-phase or joined-phase type, for a single-bar or multiple-bar system, with single-pole or three-pole actuation.
The device according to the invention therefore has a compact structure which integrates, within a single body, both the circuit-breaking elements and the disconnection elements, according to a solution which in any case allows to perform the required electrical switching operations simply and effectively.